import pandas as pd
df = pd.DataFrame({'商品':['苹果','香蕉','梨','香蕉'],
                   '单价（元）': [4,5,4,5],
                   '销量（kg）': [100,120,105,120],
                   '库存（kg）': [50,60,70,60]})
print(df)
print(df.duplicated())
print(df.duplicated('单价（元）'))
print(df.duplicated('单价（元）',keep='Last'))
print(df.duplicated('单价（元）',keep='False'))